Thick matter pump comprising a conveyance capacity control system

ABSTRACT

A thick matter pump comprising a drive motor ( 50 ), a (reversible) hydraulic pump ( 6 ), and two hydraulic cylinders ( 5, 5 ′) coupled to conveyor cylinders ( 7, 7 ′) for conveying the thick matter. A regulator regulates the rotational speed N of the drive motor ( 50 ), and a regulating clement ( 18, 20 ) regulates the displacement volume V of the hydraulic pump ( 6 ). A control module ( 54 ) regulates the rotational speed N of the motor and the displacement volume V. For improved operational ease and reduction of fuel requirements, noise and waste gas emission, the control module ( 54 ) comprises a final control element ( 56 ) for regulating the conveyance capacity of the conveyor cylinders ( 7, 7 ′), and an electronic control unit ( 108 ) which reacts to the position of the final control element ( 56 ) and allocates a nominal value to the rotational speed regulator and to the displacement volume regulator ( 20 ), in a software-assisted manner.

CROSS REFERENCE TO RELATED APPLICATION

This application is a national stage of PCT/EP02/11165 filed Oct. 4,2002 and based upon DE 101 40 467.5 filed Oct. 16, 2001 under theInternational Convention.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The invention concerns a thick matter pump with a drive motor,preferably an internal combustion engine, with at least one hydraulicpump, preferably a reversible pump having a variable displacementvolume, which can be coupled with the drive motor, with two hydrauliccylinders connected to the hydraulic pump and controlled incounterstroke (push-pull manner), each coupled to a transport orconveyor cylinder, with a regulator for regulating the rotational speedof the drive motor and a regulating element associated with thehydraulic pump for regulating the displacement volume, and with acontrol module for setting the rotational speed of the motor and thedisplacement volume of the hydraulic pump.

2. Description of the Related Art

It is further known that in thick matter pumps of this type the conveyorcylinders can be alternatively coupled to a conveyor line via a pipeswitch or shunt, wherein the conveyor line is routed along adistribution boom, which is hydraulically operable via a hydraulic pump,and is preferably in the form of an articulated boom.

In mobile concrete pumps it is known (DE-A 196 35 200) to use, in thepumping operation, the already present vehicle motor and the vehicletransmission for driving the hydraulic pump. For this purpose, a powerdrive transmission or distributor gear is generally provided in thecardanic shaft line of the vehicle, which can be selectively switchedbetween vehicle propulsion and pump operation. During pump operation thetransport or conveyance volume of the thick matter pump can be adjustedby varying of the rotational speed of the drive motor. It is furtherknown (DE-A 195 42 258) to use, for the control of the hydrauliccylinders of the thick matter pump, a hydraulic pump with variabledisplacement volume. With a given motor rotational speed, the conveyanceamount can be adjusted by regulating the displacement volume of thehydraulic pump. The known hydraulic pumps are preferably in the form ofaxial piston pumps with slant disks, of which the displacement volumecan be varied by adjustment of the slant angle of the slant disk. Theadjustment of the slant disk slant angle occurs for example via anadjustment cylinder, which for its part is controllable via aproportional valve. The pump operator thus has available to himtherewith selectively two regulating means, each independent from theother, for adjusting the desired thick matter conveyance amount. Inorder to complete the pumping operation as quickly as possible, inpractice the motor is frequently operated at maximum rotational speed,with the regulation of the amount being accomplished by adjusting thedisplacement volume alone. Therein it is not taken into considerationthat the specific fuel consumption of the drive motor is dependentprimarily upon the motor rotational speed, and that the high rotationalspeed also increases the sound emissions and exhaust gas emissions.

SUMMARY OF THE INVENTION

Beginning therewith, it is the task of the present invention to improvethe known thick matter pump with conveyance regulation of the abovedescribed type in such a manner, that for a specific conveyance amountboth the fuel consumption as well as the noise and exhaust gas emissionsare reduced.

For accomplishing this task the combination of characteristics set forthin Patent Claim 1 is proposed. Advantageous embodiments and furtherdevelopments of the invention can be found in the dependent claims.

The inventive solution is based upon the idea, that a control module isprovided, comprising a final control element or actuator for setting thethick matter conveyance capacity (F), preferably a potentiometer, aswell as an electronic control unit which reacts to the position of thefinal control element for the software supported specifying of theintended value for the regulator of the motor rotational speed and theregulating element regulating the displacement volume.

A preferred embodiment of the invention envisions that the control logicor its software includes an idle running or no load operation routinefor setting a defined no load rotational speed of the drive motor in thecase of decoupled hydraulic pump. The no load rotational speed ispreferably 20 to 50% of a predetermined maximal rotational speed.

A further preferred embodiment of the invention envisions that thecontrol logic or its software includes a base load or utility loadfactor component for setting a defined base load rotational speed of thedrive motor when coupled to the hydraulic pump.

The base load routine is activated once when, via the final controlelement, a regulating value of greater than zero (F>0) is input and apumping process is initiated. The base load rotational speed remains inthis case preferably constant over a predetermined range of settings ofthe final control element, wherein the regulating value (F) of the finalcontrol element forms a desired value or set value for the displacementvolume regulating element of the hydraulic pump.

Preferably the base load routine is also activated in the case of thezero setting of the final control element (F=0), when the distributionboom is activated. Thereby it is achieved, that during boom operation,even without a pumping process, a sufficient movement speed of thedistribution boom is achieved, which could not be achieved at only theno-load rotational speed of the drive motor.

The base load rotational speed preferably corresponds to 65 to 80% of apredetermined maximal rotational speed. It has been found particularlyadvantageous when the base load routine is activated in the settingrange below 65 to 80% of the final control element.

A further preferred embodiment of the invention envisions that thecontrol logic or its software includes a peak load routine for adjustinga defined displacement volume of the hydraulic pump, wherein thedisplacement volume remains constant over a predetermined setting rangeof the final control element and the regulating value of the finalcontrol element forms an intended value target for the rotational speedcontroller above the base load rotational speed. The peak load routineis preferably activated in an adjustment range above a predeterminedregulating value of 65 to 80% of the final control element.

A preferred embodiment of the invention envisions that, via the peakload routine, during maximal displacement volume of the hydraulic pump,rotational speeds between the base load rotational speed and apredetermined maximal rotational speed are regulated according to thevalue of a conveyance amount regulated by the final control element. Themaximal rotational speed is preferably greater than 1,700 RPM.

In order to prevent an overload of the system, it is proposed inaccordance with a further preferred embodiment of the invention that asensor is provided on the pressure side of the hydraulic pump fordetecting the hydraulic pressure and/or the pump output, and that thecontrol module or its software includes a limiting routine responsive toa predetermined pressure or output value for reducing the displacementvolume.

BRIEF DESCRIPTION OF THE DRAWING

In the following the invention will be described in greater detail onthe basis of the figures. There is shown

FIG. 1 a a hydraulic flow diagram of a two cylinder thick matter pump;

FIG. 1 b a schematic of a control module for regulating the conveyanceamount in the thick matter pump according to FIG. 1 a;

FIGS. 2 a and b a flow diagram of a control software for the regulationof the conveyance amount;

FIG. 3 a diagram which shows the motor rotational speed and the relativedisplacement volume of the hydraulic pump depending upon the setting orcontrol of the final control element for the thick matter conveyanceamount.

DETAILED DESCRIPTION OF THE INVENTION

The hydraulic flow diagram shown in FIG. 1 is designed for a thickmatter pump, which includes two conveyor cylinders 1, 1′, of which theend openings 2, 2′ open into not shown material supply containers, andwhich are alternatively in communication, via the pipe switch 3, with aconveyance line 4 during the pressure stroke. In a thick matter pump,which here is a concrete pump, the conveyance line continues along a notshown hydraulically operated concrete distribution boom which ispreferably in the form of an articulated boom. The conveyor cylinders 1,1′ are operated in counterstroke via the hydraulic cylinders 5, 5′ andthe reversible hydraulic pump 6 which in the illustrated embodiment isin the form of a slant disk axial piston pump. For this purpose theconveyor pistons 7, 7′ are connected with the drive pistons 8, 8′ of thehydraulic cylinders 5, 5′ via a common piston rod 9, 9′. Between theconveyor cylinders 1, 1′ and the hydraulic cylinders 5, 5′ there is awater chest 10 through which the piston rods 9, 9′ extend.

In the shown illustrative embodiment the drive cylinders 5, 5′ are actedupon on their base side by hydraulic oil via the hydraulic lines 11, 11′of the main flow circuit by means of hydraulic pump 6 and are connectedhydraulically with each other via a rocker hydraulic line 12. For thepurpose of stroke correction, there is provided on both ends of thehydraulic cylinders 5′ of each of the concerned drive pistons 8′ apressure equalization line 14 containing a check valve or non-returnvalve 13 bridging over the end position.

The direction of movement of the drive pistons 8, 8′, and therewith theconveyor pistons 7, 7′, is reversed thereby, that the slant disks 15,15′ of the reversing pump 6, triggered by a reverse signal, pivotthrough their zero position and therewith change the direction ofconveyance of the hydraulic oil in the hydraulic lines 11, 11′ of thehydraulic flow circuit. The operating of the conveyance direction of thereversing pump 6 determining main control valve 20 occurs via theelectrically picked off end position signal x and xx of the drivecylinder 5. The displacement volume V of the reversing pump 6, andtherewith the hydraulic conveyance amount, is determined by the slantangle of its slant disk 15, 15′ and by the rotational speed N of thedrive motor 50, which is preferably a diesel motor. The slant disk angleis adjustable proportional to a control pressure, which operates via thelines 17 and 17′ and the proportional valve 20 of the control cylinder18 located in the relevant circuit or flow path. The high pressure levelcan be changed or changed over depending upon the value of the switch orcircuit condition of the thick matter pump via the blocking or closingvalve 95 and the two pressure limiting valves 70, 70′ while, foradjusting the low pressure level, a pressure regulator 71 is provided.The control inputs for the hydraulic cylinders are connectable with therespective high pressure or, as the case may be, low pressure conveyinglines 11, 11′ of the main circuit via the switch or rocker valve 72 or,as the case may be, a directional valve 73 in the form of a rinse orflush valve.

The auxiliary pump 25 charges the closed main flow circuit via the checkvalve 75, 75′ and is protected by high pressure limiting valve 74.

The change over of the pipe switch 3 occurs via the hydraulic cylinders21, 21′ which are in the form of a plunger cylinders, which are actedupon directly with the hydraulic fluid conveyed from the reversing pump6 through the control lines 22, 22′ branched off from the hydrauliclines 11, 11′ of the main flow circuit and the reversing valve 30.

For setting the conveyance amount of the thick matter pump two basicparameters are available: The rotational speed N of the drive shaft 52of the drive motor 50 coupled with the hydraulic pump 6 and thedisplacement volume V of the hydraulic pump 6 defined by the angularposition of the slant disk 15 of the hydraulic pump 6. The setting ofthis parameter occurs via a control module 54, which is integrated intoa radio control device operable by the pump operator. To adjusting theconveyed amount F a final control element 56 in the form of apotentiometer is available to the pump operator, which can be adjustedby hand between the positions 0 and 100%. In the 0 position no concreteis conveyed, while in the 100% position the maximal conveyance amount isselected. In each intermediate position a corresponding proportion ofthe maximal conveyance amount is conveyed corresponding to the indicatedpercentile position. The control module further includes a control logic108 responsive to the setting of the final control element 56 for thesoftware supported target value input for the rotational speed regulatorof the motor 50 and for the angular position of the slant disk 15 whichdefines the displacement volume of the hydraulic pump 6. The actualregulation of the rotational speed occurs in the control module 54. Forthis, the control module 54 obtains the actual rotational speed from arotational speed gauge or meter 100 and is connected via outputs 101 and102 with the inputs N+ and N− of the motor N. Herein N+ means “givegas”, N− means “reduce gas”. In the regulating element 20 for theadjustment of the displacement volume of the hydraulic pump 6, it is inthis case a proportional valve, via the different path positionssimultaneously the strokewise reversing of the hydraulic pump occursbetween the two drive cylinders 5, 5′. For adjusting the displacementvolume V a control module 54 is connected via connection 103 to theelectromagnets of the electrically operated proportional valve 20. Thevalve current reaching the connections 103 is calculated in the controllogic 108 via the control software and is set by pulse width modulation.The control module 54 includes besides this also a connection 104 for apressure sensor in the hydraulic circuit, which provides supplementalpressure information P for output control and pressure limitation.

The control software is described in greater detail in the following onthe basis of the flow diagram shown in FIG. 2 a,b. The program includesmultiple branches, which in the following will be referred to as“routines”. The pump 6 can be switched on and off using the remotecontrol via a not shown switch. The activation condition of the pump isrecognized in the control module by a signal at input 80. The controlmodule 54 obtains a signal regarding the operating condition of thedistribution boom via a further input 82.

In the case of switched off pump, switched off boom operation and aninput value F=0 at the final control element 56 the software question110 leads, over the output path “no”, to a no-load routine 112, viawhich a defined no-load rotational speed of the drive motor of N=850 RPMis set. The adjustment of the rotational speed occurs by a controlparameter N− at the connection 102 (FIG. 1). The no-load rotationalspeed ensures that the motor overcomes the no-load friction, withoutstalling.

Upon activation of the pump 6 (input 80) or during boom operation (input82) or during operation of the control element 56 the control logic orit's software 108 arrives, via the “yes” path of the question 110, tothe base-load routine 118′, in which the rotational speed of the motoris increased by giving gas (N+) up to the base-load rotational speedN=1,300 RPM. This rotational speed is selected, for example, for aparticular type of motor, depending upon the value of a minimal fuelconsumption for a sufficient torque for the trouble-free operation ofthe pump. After reaching the base-load rotational speed it is checked inthe software branch 115 whether mast operation is occurring without pumpoperation. If this is the case (“yes” at 115), then the questioning isended and the program jumps back to program start 110.

In the case that the pump is switched on (“no” at 115) then the controlsoftware reaches branch 114, which ensures that next the intended valueF set at the control means 56 is read and compared in the softwarebranch 116 with a preset benchmark value EOC. So long as the regulatingvalue F is below the benchmark value EOC (“yes”), the second branch ofthe base-load routine 118″ is run, wherein the base-load rotationalspeed N=1,300 RPM is here set by reduction of gas (N−). Then the valvecurrent for the connections 103 of the proportional valve 20 arecalculated to provide an output or flow depending on the value of theconveyance amount F set at final control element 56 in the program part120. The adjusted valve current determines the displacement volume V ofthe pump 6. The valve flow or path can be increased so long until thehydraulic pump 6 is adjusted to the greatest tilt angle, in which casethe pump 6 is operating with the greatest displacement volume (V=100%).As soon as the adjustment value F of the adjustment body 56 exceeds theEOC benchmark value, then the control software enters into the area ofthe peak-load routine 122, in which with maximal displacement volume Vof the pump 6 a further increase in the conveyance amount is achieved byincreasing rotational speed N of the motor. The respective rotationalspeed is calculated in the program area 124 with development of thevalue N_(intended) and is matched with the measured actual value bycontrolling the motor input N+ or as the case may be N−. At the sametime the maximal displacement volume (V=100%) is maintained via theprogram part 126.

The program parts 120 and 126 are connected at their output side with acheck routine 128, in which it is checked with evaluation of thepressure signal P detected with the sensor 104 whether a predeterminedoutput pressure limit is reached. In the case “yes” the valve flow inthe proportional valve 103 is reduced for adjusting the displacementvolume V in the program part 130, if “no” the instantaneous setdisplacement volume V remains maintained. From there, a return to theprogram start 110 occurs. There the next program part is initiated.

The program defined by the flow diagram according to FIGS. 2 a and bleads to the shown intended value running of the motor rotational speedN shown in the diagram according to FIG. 3 and the displacement volume Vdepending upon the adjustment of the displacement amount F at finalcontrol element 56. The pump motor, in the case that the conveyanceamount F=0, starts with the no-load rotational speed of 850 RPM and isadjusted to the base-load rotational speed of 1,300 RPM upon switchingon of the pump (curve N with quadratic measurement points). Duringadjusting of the final control element 56 the motor rotational speed ismaintained constant at the base-load value, while the displacementvolume V is increased linearly with the control value F of the controlbody 56. Upon reaching the EOC benchmark value (F=74%) the displacementvolume of the pump is set to V=100%. From there onwards, an increase inthe conveyed amount is achieved exclusively by increasing the motorrotation speed N, until the maximum conveyance amount (F=100%) isachieved at a rotational speed of approximately 1,750 RPM.

In summary, the following can be concluded: The invention relates to athick matter pump comprising a conveyance capacity control system. Saidthick matter pump comprises a drive motor 50 which is preferablyembodied as an internal combustion engine, a hydraulic pump 6 which ispreferably embodied as a reversible pump, which has a variabledisplacement volume V and can be coupled to the driving motor, and twohydraulic cylinders 5, 5′ which are connected to the hydraulic pump 6,can be controlled by the same in a push-pull manner, and are eachcoupled to a conveyor cylinder 7, 7′ for conveying the thick matter. Aregulator for regulating the rotational speed N is associated with thedrive motor 50, and a regulating element 18, 20 for regulating thedisplacement volume V is associated with the hydraulic pump 6. A controlmodule 54 is also provided for regulating the rotational speed N of themotor and the displacement volume V. According to the invention, thecontrol module 54 comprises a final control element 56 for regulatingthe thick matter conveyance capacity F of the conveyor cylinders 7, 7′,and an electronic control unit 108 which reacts to the position of thefinal control element 56 and allocates a nominal value to the rotationalspeed regulator and to the displacement volume regulator 20, in asoftware-assisted manner. These measures enable improvement of theoperational ease of the thick matter pump, and reduction of fuelrequirements, noise emission and waste gas emission during practicaluse.

1. A thick matter pump comprising: a drive motor (50), a variabledisplacement hydraulic pump (6) coupelable to the drive motor, twohydraulic cylinders (5, 5′) connected to the hydraulic pump and drivenin counterstroke, one conveyor cylinder (7, 7′) coupled respectively toeach hydraulic cylinder, a rotational speed regulator for regulating therotational speed of the drive motor, a displacement volume regulator(20) associated with the hydraulic pump for regulating the displacementvolume, and a control module (54) for regulating the thick matterconveyance capacity by regulating (a) the rotational speed of the motorand (b) the displacement volume of the hydraulic pump via the rotationalspeed regulator and the displacement volume regulator (20), wherein thecontrol module (54) includes a final control element (56) for selectingthe desired thick matter conveyance capacity (F) of the conveyorcylinders (7, 7′) and an electronic control unit (108) which reacts tothe position of the final control element (56) and allocates a nominalvalue to the rotational speed regulator and to the displacement volumeregulator (20) in a software assisted manner, wherein the electroniccontrol unit (108) or its software includes a base-load routine (118,118′) for adjusting a defined base-load rotational speed of the drivemotor (50) in the case of coupling to the hydraulic pump (6), whereinthe base load rotational speed remains at a constant rotational speedbelow a predetermined maximum rotational speed over a predeterminedadjustment range of the final control element (56) and wherein when thebase load rotational speed is at the constant rotational speed theadjustment value (F) of the final control element (56) provides anintended value input for the displacement volume (V) of the hydraulicpump (6).
 2. A thick matter pump according to claim 1, wherein the finalcontrol element (56) is a potentiometer.
 3. A thick matter pumpaccording to claim 1, wherein the conveyor cylinders (7, 7′) arealternatively coupleable to a conveyance line (4) via a pipe switch (3),runs along a distribution boom, preferably an articulated boom, which ishydraulically operated via a hydraulic pump (6), thereby characterized,that the base-load routine (118, 118′) is activated in the case that thedistribution boom is switched on even in the case of the zero positionof the final control element (56) and/or the case of the switched offpump operation.
 4. A thick matter pump according to claim 1, wherein thebaseload rotation speed corresponds to 65 to 80% of a predeterminedmaximal rotational speed.
 5. A thick mailer pump according to claim 1,wherein the base load rotational speed is selected to be a constantvalue (N) between 1,200 and 1,500 RPM.
 6. A thick matter pump accordingto claim 1, wherein the base-load routine (118) is activated in anadjustment area below 65 to 80% of the final control element (56).
 7. Athick matter pump according to claim 1, wherein the electronic controlunit (108) or its software includes a peak-load routine (122) foradjusting a defined displacement volume (V) at the hydraulic pump (6),wherein over a predetermined adjustment range of the final controlelement (56) the displacement volume (V) remains constant and theregulating value (F) of the final control element (56) forms an intendedvalue (N_(intended)) for the drive motor rotational speed regulatorabove the base-load rotational speed.
 8. A thick matter pump accordingto claim 1, wherein a sensor (104) is provided on the pressure side ofthe hydraulic pump for detecting the hydraulic pressure (P) and/or thepump output, and that the control module (54) or its software (108)includes a limiting routine (128) responsive to the measured pressure oroutput value (N) for reducing the displacement volume (V) in the case ofexceeding a predetermined limitation value.
 9. A thick matter pumpaccording to claim 1, wherein the electronic control unit (108) or itssoftware includes a no-load routine (112) for setting a defined no-loadrotational speed of the drive motor (50) in the case that the hydraulicpump (6) is decoupled.
 10. A thick matter pump according to claim 1,wherein said drive motor is an internal combustion engine.
 11. A thickmatter pump according to claim 1, wherein said pump is a reversiblepump.
 12. A thick matter pump comprising: a drive motor (50), a variabledisplacement hydraulic pump (6) coupelable to the drive motor, twohydraulic cylinders (5, 5′) connected to the hydraulic pump and drivenin counterstroke, one conveyor cylinder (7, 7′) coupled respectively toeach hydraulic cylinder, a rotational speed regulator for regulating therotational speed of the drive motor, a displacement volume regulator(20) associated with the hydraulic pump for regulating the displacementvolume, and a control module (54) for regulating the thick matterconveyance capacity by regulating (a) the rotational speed of the motorand (b) the displacement volume of the hydraulic pump via the rotationalspeed regulator and the displacement volume regulator (20). wherein thecontrol module (54) unit includes a final control element (56) forselecting the desired thick matter conveyance capacity (F) of theconveyor cylinders (7, 7′) and an electronic control unit (108) whichreacts to the position of the final control element (56) and allocates anominal value to the rotational speed regulator and to the displacementvolume regulator (20) in a software assisted manner, wherein theelectronic control unit (108) or its software includes a peak-loadroutine (122) for adjusting a defined displacement volume (V) at thehydraulic pump (6), wherein over a predetermined adjustment range of thefinal control element (56) the displacement volume (V) remains constantand wherein the regulating value (F) of the final control element (56)forms an intended value (N_(intended)) for the drive motor rotationalspeed regulator above a base-load rotational speed.
 13. A thick matterpump according to claim 12, wherein a peak load routine (122) isactivated in an adjustment range above a regulation value of 65 to 80%of the final control element (56).
 14. A thick matter pump according toclaim 12, wherein via the peak load routine (122), in the case ofmaximum displacement volume (V) of the hydraulic pump (6), rotationalspeeds between the base-load rotational speed and a predeterminedmaximal rotational speed can be set depending upon the value of theconveyance amount (F) input at the final control element (56).
 15. Athick matter pump according to claim 14, wherein the predeterminedmaximal rotational speed is at least 1,700 RPM.
 16. A thick matter pumpaccording to claim 12, wherein a sensor (104) is provided on thepressure side of the hydraulic pump for detecting the hydraulic pressure(P) and/or the pump output, and that the control module (54) or itssoftware (108) includes a limiting routine (128) responsive to themeasured pressure or output value (N) for reducing the displacementvolume (V) in the case of exceeding a predetermined limitation value.17. A thick matter pump according to claim 12, wherein the electroniccontrol unit (108) or its software includes a no-load routine (112) forsetting a defined no-load rotational speed of the drive motor (50) inthe case that the hydraulic pump (6) is decoupled.
 18. A thick matterpump according to claim 17, wherein the no-load rotational speedcorresponds to 20 to 50% of a predetermined maximal rotational speed.19. A thick matter pump according to claim 17, wherein the no-loadrotational speed is 700 to 900 RPM.
 20. A thick matter pump according toclaim 12, wherein said drive motor is an internal combustion engine. 21.A thick matter pump according to claim 12, wherein said pump is areversible pump.